No abstract

No abstract

The prediction of additional stresses in ballasted track due to subgrade deformation is the main objective of the present paper. In this context, a 2D finite element model of ballasted railway track was built using the ANSYS Workbench program. Based on this model, an investigation of stresses and deformation values of track elements was conducted in three cases with different contact types. It was found that the case introducing the status of a new track, which has frictional contacts between sleepers and ballast with bonded contacts between other elements, has lower stresses in most of the track elements. Moreover, this case was applied for studying the effect of the settlement on track elements. It was found that stresses increased with increasing the settlement value. The average percentages of increased stresses are 4.18%, 5.85%, and 7.21% in railhead, tie plate, and sleeper, respectively, due to a 1 mm increase in the settlement. Finally, a second-degree polynomial equation was derived to predict the additional stresses in each element due to track settlement. It is expected that this study would help to decrease the maintenance costs and extend the service life of the track elements by predicting the additional stresses in them.

No abstract

No abstract

The noise levels inside metro units are considered a significant problem that makes passengers suffer from severe damage, especially for those who use the metro periodically. This research evaluates the acoustic environment inside the metro car and studies factors affecting the noise levels inside metro units and developing models for estimate noise in the metro unit while moving between stations. Greater Cairo Metro (GCM) Line 1 has been selected as a case study. A sound level meter was used to measure the equivalent sound level in dBA and evaluate the noise inside metro units. The results indicate that the noise levels are unacceptable compared with the international noise exposure standards. The highest measured noise level inside metro units is 91.2 dBA. These unacceptable noise levels led to more investigation of factors that may affect noise levels inside metro units. Other data have been collected, such as the speed of the train and the track alignment details. The results showed that the noise increases with the increase of the train speed until the speed reaches a specific value, then it decreases depending on the maintenance status and the train type. In addition, the noise levels through curved underground tracks are higher than the levels along straight surface tracks by 18 dB(A). Doi: 10.28991/cej-2021-03091674 Full Text: PDF

No abstract

Metro has become one of the most used means among public transit due to its advantages such as mass transit capacity, safety, fast speed, and comfort. Despite its benefits, workers and passengers ride the metro daily, and they are continuously being exposed to a high level of noise. Noise exposure has been related to various health-related issues. This paper presents an evaluation of the acoustic environment at the station’s platform and studies factors affecting the platform’s noise levels. Greater Cairo Metro Line 1, 2, and 3 have been selected as a case study. The result indicates that noise levels are unacceptable compared with the international standards of noise exposure as the highest measured noise level at station platforms was 93.93 dB(A). Regarding the rolling stocks type, the L Aeq was different from one type to another, with a range of 2.28 to 6.5 dB(A). The L Aeq on the underground platforms station was 11 dB(A) higher than on the surface stations regarding the station type. For underground stations, the L Aeq on curved platforms higher than the straight platforms when a train arrived, stop and go from the station with a range of 2.7 to 4.9 dB(A). Regarding the station platform dimension, the L Aeq on the underground platforms with a 5 m width is higher than the one with a 3 m width by 3 dB(A).